Debarking machine

ABSTRACT

A debarking machine of the type in which roller-shaped debarking tools are pressed inwardly by pivoting arms against a log, as they rotate around the log, includes a mechanism for controlling rotation of the roller-shaped debarking tools about rotational axes disposed longitudinally to the pivoting arms. The mechanism prevents such rotation when the tools are not completely on a log and allows such rotation at other times. A drive mechanism provides variable inward bias pressures for the roller-shaped debarking tools and a disabling device disables this inward bias to allow a new log to be inserted in the debarking machine.

United States Patent [191 Braun 14 1 Oct. 21, 1975 [73] Assignee: Maschinenfabrik Braun KG,

Germany 22 Filed: Apr. 19, 1974 21 Appl. No.: 462,499

[30] Foreign Application Priority Data Apr. 21, 1973 Germany 2320450 [52] US. Cl. 144/208 E; 83/370; 144/208 R [51] Int. Cl. B27L 1/00 [58] Field of Search 144/208 R, 208 E, 208 F; 83/368, 370, 371

[56] References Cited UNITED STATES PATENTS 2,591,751 4/1952 Whitlock 144/208 E 2,646,092 7/1953 Kolpe et al 144/208 E 2,671,480 3/1954 Efurd, Jr. et al. 144/208 F 3,263,720 8/1966 Brock et al 144/208 F 3,554,249 1/1971 Arnelo 3,774,660 11/1973 Morey et al. 144/208 F 3,789,893 2/1974 Carson et a1. 144/208 E FOREIGN PATENTS OR APPLICATIONS 41,554 11/1916 Sweden 144/208 E Primary ExaminerFrank T. Yost Assistant ExaminerW. D. Bray Attorney, Agent, or Firm-Griffin, Branigan & Butler [5 7 ABSTRACT A debarking machine of the type in which rollershaped debarking tools are pressed inwardly by pivoting arms against a log, as they rotate around the log, includes a mechanism for controlling rotation of the roller-shaped debarking tools about rotational axes disposed longitudinally to the pivoting arms. The mechanism prevents such rotation when the tools are not completely on a log and allows such rotation at other times. A drive mechanism provides variable inward bias pressures for the roller-shaped debarking tools and a disabling device disables this inward bias to allow a new log to be inserted in the debarking machine.

U.S. Patent Oct. 21, 1975 Sheet 1 Of4 3,913,644

FIG. I

Sheet 2 0f 4 3,913,644

US. Patent Oct. 2l, 1975 US. Patent Oct. 21, 1975 Sheet 3 of4 3,913,644

FIG. 2a

FIG. 30 W US. Patent Oct. 21, 1975 Sheet40f4 3,913,644

DEBARKING MACHINE FIELD OF THE INVENTION This invention relates to debarking machines of the type comprising an annular debarking rotor rotating about a log to be debarked and having arms which pivot about axes arranged parallel to the rotor axis and which are adapted to be forced against the log in a radial direction relative to the rotor axis and which carry substantially roller-shaped debarking tools rotating about axes located substantially parallel to the rotor axis.

DISCUSSION OF PRIOR ART Such debarking machines are known from Swedish Pat. No. 41,554. They have the disadvantage that the high cutting efficiency of roller-shaped milling tools cannot be adapted sufficiently to the unevenness of logs to be debarked, and that regulation of the pressure of the debarking tools against the log to be debarked is not readily possible because a singular unevenness in a small marginal region of the operating width of the roller-shaped milling cutters, for example, would cause a full response of the regulator so that the debarking result would not be satisfactory.

SUMMARY OF THE INVENTION Accordingly, it is one object of the invention to construct a debarking machine of the above-mentioned type so that the debarking tools can adapt themselves to a log to be debarked to such an extent that the debarking effectiveness of the debarking tools will be fully utilized and the debarking can take place with small loss of wood.

According to the invention, this problem is solved in that said pivotal arms are rotatable about a rotational axis extending perpendicular in the pivot axis and pointing substantially to the longitudinal direction of the pivoting arms.

This embodiment permits the debarking tools to perform a tilting movement in addition tothe pivotal movement toward the log surface or away from the surface so that the roll-shaped debarking tools can practically ride away over the unevennesses.

Suitable embodiments of the debarking machine of the invention are moreover subject matter of the attached subclaims.

BRIEF DESCRIPTION OF THE DRAWINGS Some exemplary embodiments will be elucidated in greater detail hereinafter with reference to the attached drawings in which FIG. 1 shows a schematic perspective view of a debarking machine with great simplification of the means for feeding the logs to be debarked,

FIG. 2 shows one part of the debarking rotor in sectional view together with a single arm pivotally mounted and rotatable therein,

FIG. 2a shows an axial section through the debarking rotor in the range of a pivotal and rotary hinge for the pivoting arm,

FIG. 3 shows a view of another embodiment corresponding to FIG. 2, and

FIG. 3a shows a view of a section through the debarking rotor according to FIG. 3 corresponding to FIG. 2a.

In a frame construction omitted from FIG. 1 for the sake of simplification of this illustration, there are schematically shown feed means 1 and 2 mounted therein, by means of which the log 3 to be debarked is fed to the debarking rotor 4 of the debarking machine in the axial direction at a predetermined constant height. A corresponding arrangement of feed means 1 and 2 is provided at the opposite side of the debarking rotor in order to remove the debarked log from the debarking rotor or to allow the feeding of a log to be debarked from the opposite side (this is not shown in FIG. 1 also for the sake of simplification of the illustration). The debarking rotor 4 is rotatably mounted in a housing 5 which is supported via an arrangement of rocker means in relation to a machine base shown schematically at 7 and which, though not shown in detail, can be horizontally moved transversely of the rotor axis and can be interchanged with a spare housing having fresh debarking tools. A fluid pressure drive 8 permits adjustment in height of the rotor axis of rotation via coupling rods 9 in a manner such that said axis coincides with the axis of the log to be debarked. Such adjustment can take place automatically in response to a measuring signal produced, for example, via a sensing drum l0 and a measuring signal generator 11.

At the debarking rotor 4 are mounted arms 12 which are adapted to be pivoted about pivot axes located parallel to the rotor axis and which have their ends carrying roller-shaped debarking tools 13 adapted to be rotated about axes which are also substantially parallel to the rotor axis. In the present case, the debarking tools 13 are formed of outside-rotor electric motors carrying the debarking knives at outside-rotor and adapted to be supplied with electrical power via slip rings (not shown) on the debarking rotor 4. However, for driving the debarking tools, hydraulic or compressedair motors may also serve, which are arranged at the ends of the pivoting arms and which are supplied with fluid by a fluid pressure source on the debarking rotor and rotating therewith.

The sensing drum 10 and the measuring signal generator 11 have the further task to indicate the respective positions of the log end faces by signals indicating a starting position, for example, so as to initiate the engagement movement of the pivoting arms 12 after a predetermined path of advance when the logs leading end has reached the rotor center, after a temporary stoppage of the advanceof the log. Then, when the debarking tools have reached a certain forcing pressure which is indicated by a device to be described hereinafter, the advance of the log is started again. The measuring signal generator 11 delivers a further positionindicating signal when the logs leading end face has travelled forward so far that the debarking tools are completely lying on the log, whereupon a debarking function is carried out at the pivoting arms, as will be discussed more exactly hereinafter.

The slip rings provided in a sufficient number for the current supply of the outside rotor motors and for diversely controlling driving (to be also described hereinafter) the debarking rotor are mounted at a rotor, end face and encapsulated in the housing 5 so that dirtying by wood chips or dust is reliably avoided.

FIG. 2 shows the mounting construction of a single pivot arm 12 in sectional view. A foot 14 of each arm 12 is pivotally mounted via pivot pins 15 in corresponding eyes of the debarking rotor 4 to rotate about a pivot axis 16 extending parallel to the rotor axis. In addition, each pivoting-arm foot 14 includes a bearing 17 for a pivot pin 18 of the respective pivoting arm E2 in a manner such that the pivoting arm is rotatable about a rotational axis l9pointing substantially in the longitudinal direction of said pivoting arm. Due to the offset bend of the pivoting arm l2 as shown in HQ. 2., the rotation axis 19 substantially constitutes a tangent to the outer circumference of the debarking tool l3 so that this tool, when exerting a predetermined pressure, maintains a stable position by a bias momentum acting about the pivot axis 16.

At the side of the pivoting-arm foot li iremote from the pivoting arm 12, there is provided a counterweight or balance weight 2th the mass of which is selected so that the center of gravity of the system of the debarking tool 13, the pivoting arm 12, the pivoting-arm foot 14 and the counterweight 20 is placed substantially on the pivot axis 16. in this manner it is achieved that the foreing pressure of the debarking tool 13 does not vary when the rotational speed of the debarking rotor 4 varies.

At the counterweight 2th there is fastened one end of a spiral spring 2i, the other end of which is anchored at a bolt 23 fixedly connected to a ring 22. The ring 223 is coaxial with the debarking rotor 1 and is rotatable in slide bearings 24 relative to the debarking rotor 4- by means of a drive 25 having a pinion 26 meshing with a peripheral toothing of the ring The drive 25, in the case of the present embodiment, has the form of an electric motor which is connected to the slip rings of the debarking rotor i and which can be energized for performing a predetermined adjustment movement during the rotation of the rotor so that the ring 22 can be rotated and thus the position of the bolt 23 can be varied relative to the fastening point of the spiral spring 21 with the counterweights 2i), whereby the bias torque about the pivot axis in, and hence the forcing pressure of the pivoting arms 12,, is varied.

A number of modifications for the drive connection of the adjustment drive 25 with the ring 2.2 may be obvious for the man skilled in the art. it is also possible to use a hydraulic drive in place of the electric motor.

which hydraulic drive is supplied by a hydraulic pump mounted on the debarking rotor 4i and rotating therewith. The control of the drive takes place then by the actuation of corresponding valve means, the electrogmagnetic drives of which can be excited via slip rings of the debarking rotor.

Parallel to the spiral spring 21 and between the counterweight 2d and a bolt there is connected a coupling means which is formed ofa rack 27 and a rack guide 28. The coupling has an actuating magnet 29 mounted on the rack guide 22'} for actuating a latch adapted to be moved into the toothing of the rack 27. The latch 30 is self-holding relative to the toothing of the rack 27 in a manner such that after the latch 36 has been pushed in by a short-time energization of the magnet 29 the latch 3t} remains in the engaged position due to the force of the spiral spring 2i... The latch prevents the rack 27 and the rack guide Eli from being telescoped into each other until the latch fit]? drops out from the position of engagement under the action of a (not shown) return spring by still further expanding the spiral spring El and thus the rack 2'7 and the rack guide 28.

The above-described structure permits that after an operational cycle under a predetermined forcing pres sure produced by the extension of the coil springs 72?.

The electrical connections to the magnet ji ifare shown at The connections have interconnection with the sliprings of the debarking rotor i. Further slip rings make the connection to terminals schematically shown at 3.2 of a potentiometer arrangement serving as position indicator for the relative position of the rack 2'7 and of the rack guide 2%, andthus as an actual-value-signal generator for the forcing pressure of the pivoting arms 32. if a control device, the structure of which may be known to those skilled in the art, is interposed between the terminals 3 2 of the potentiometer assembly 33 and the drive 25 for adjusting the ring 22, the forcing pressure of the debarking tools can be adjusted to a desired value.

For performing predetermined dcbarking operations i and for avoiding a tilting movement of the debarking arms 12 about their axes W of rotation at the beginning and at the end of a passage of the log 3 while the debarking tool H3 is not fully abutting the log surface, it may be suitable to temporarily block the rotatability of the pivoting arms 12 about the axes 39, as is possible during the rotation of the rotor lin the case of the illus' trative example as shown. From FlG. 2a it is apparent that the pivot axis to and the rotation axis of the piv oting arms 12 intersect each other in one point. Through a coaxial bore ofa bearing pin llii of the pivoting arm foot M locking bolt is insertable into, a bore 35 of the pivot pin 18 of the pivoting arm. in this connection the locking bolt 34 is provided. for example, with a thread 36 and is axially movable relative to the debarking rotor past a guide means 37 which gages an axial groove of the locking bolt 34 to secure it against rotation. A bush 38, provided with anintcr rial thread and mounted coaxially to the pivot axis in the debarking rotor 41-, is effective to cause, by its rotation. an advancing or a withdrawal of the locking bolt for re leasing the pivot pin 18 and thus the pivoting arm l2 for rotation about the axis 2%. The bush 3% can be actuated by a separate electrical control drive w connected to sliprings of the debarking rotor 4 during the rotation of the rotor; or, as shown in FIG. 2a, by a toothed rim 3) engaging the toothing provided on inner cir cumference of a ring it). The ring 46 is arranged coaxial to the debarking rotor d and is mounted in a sitn ar manner to be rotatable relative to the rotor as was mentioned before in conjunction with the description of the ring Accordingly, the ring m can be rotated by means ofa single servo drive ll and this permitsthe actuation of the locking bolts 1% of the debarking rotor 4.

in 21; there are shown moreover V-belts 4,2 which are laid into corresponding grooves of. the debarlting rotor 4 and which are placed over a if-belt pulley of a drive motor for driving the rotor.

While, in the ease of the exemplary embodiment according to H6. control drive 725 is serving forthe ad justment of the forcing pressure of the debarlaing tools or all pivoting arms l3 and is provided in common for all pivoting arms, in the case of the exemplary embodiment according to FIG. 3 there is provided for each pivoting arm 12 a separate servomotor 43, secured to the pivoting arm foot 14 and constituting part of the couterweight. The servomotor 43 is connected to sliprings of the debarking rotor 4 via (schematically shown) connections 44. Just as for the before-mentioned drive and control motors, the servomotor 43, instead of an electric motor, could be a hydraulic motor which is supplied via a hydraulic pump rotating with the debarking rotor 4 and which is controlled via electrically operated valves, the valve drives being connected to sliprings.

A pinion 45 of the servomotor 43 meshes with a toothed rim 46 of a sleeve 47 which is rotatable relative to the debarking rotor 4 and which may be mounted rotatably on a bearing eye 48 for the bearing pin 15 in the manner shown in FIG. 3a. At a circumferential point of the sleeve 47, designated by 49, there is anchored a flexible coupling element such as a chain or a wire cable 50 in a manner such that said coupling element, upon single or multiple winding around the sleeve 47 in the indicated direction, can be led from the anchoring point 49 over a deflecting pulley 51 to one end of the coil spring 21, the other end of which is firmly connected to the debarking rotor 4 at 52. In the event that, with respect to the mutual position of the members according to FIG. 3, the sleeve 47 is rotated by a predetermined angle by means of the control motor 43 relative to the pivoting arm 12, the expansion of the coil spring 21 can be varied and thus the bias torque and the forcing pressure at the debarking arm 12 can be adjusted.

A structure corresponding to the rack 27, the rack guide 28 and the latch 30 according to FIG. 2 is formed, in the embodiment according to FIGS. 3 and 3a, by a ratchet 30' which is actuated by a drive 29 and which is mounted on the debarking rotor 4 and engages into a toothed rim 27 of the sleeve 47. The ratchet 30' and the toothed rim 27' are designed so that, when the ratchet is pushed in by the drive 29, a self-holding of the sleeve 47 relative to the debarking rotor 4 occurs by the force exerted on the sleeve 47 by the coil spring 21 via the coupling element 50 so that the pivoting arm 12 can be immediately lifted from the log being debarked by the actuation of the drive 43 without the necessity to completely relieve the coil spring 21 by rotating the sleeve 47 back, while the case of actuation of the control motor 43 such that the spring 21 is further expanded by virtue of rotation of the sleeve 47 counterclockwise, the ratchet 30' will immediately fall out from its locked position due to the force effect of a return spring (not shown).

It should be also mentioned that, between the sleeve 47 and the debarking rotor 4 there can be interposed a rotation potentiometer which serves as an actualvalue-signal generator corresponding to the potentiometer arrangement 33 of the embodiment described before. However details in this respect are omitted from FIGS. 3 and 3a for the sake of simplicity of the illustration.

It is also to be noted that the embodiments described may be modified so that they can be used as round reducing machines in that all pivoting arms are positively coupled to each other relative to the pivotal movement e.g. in that, in contradistinction to the embodiment according to FIG. 2, they are coupled to the ring 22 via 6 rigidcouplingmeans instead of springs 21, said ring 22 being rotatable relative to the debarking rotor 4 against spring force.

I claim:

l. A debarking machine comprising an annular debarkingrotor rotating about a log to be debarked and having arms for pivoting about pivot axes located parallel to the rotor axis to press against the log in radial di- .rections relative to the rotor axis, said arms including substantially cylindrical-roller-shaped debarking tools rotating about axes located substantailly parallel to the rotor axis, and said pivoting arms being respectively rotatable about rotational axes extending approximately normal to said pivot axes, said rotational axes being respectively orientated substantially in the longitudinal direction of the pivoting arms.

2. A debarking machine according to claim 1 in which the rotational axes of said arms constitute substantially tangents to the circumferences of the respective debarking tools in or near to the points of contact with the log to be debarked.

3. A debarking machine according to claim 1, comprising a locking means for temporarily locking the pivoting arms against rotating movement about said rotational axes.

4. A debarking machine according to claim 3 wherein said pivot axes and said rotational axes of the pivoting arms intersect each other at respective points and wherein said locking means comprise locking bolts movable coaxially to said pivot axes into bores of shafts being located at said rotational axes.

5. A debarking machine according to claim 4 wherein said locking bolts are threaded and wherein are further included threaded bushings having toothed rims, a toothed ring for meshing with said threaded bushings and which is coaxial to the debarking rotor, and a servomotor means for rotating said toothed ring.

6. A debarking machine according to claim 5, wherein said servomotor means comprises an electric motor supplied with electric energy.

7. A debarking machine according to claim 5, wherein said servomotor means comprises a hydraulic motor supplied with pressurized fluid by a hydraulic pump of the debarking rotor.

8. A debarking machine according to claim 3, and further including an electromagnetic drive means for actuating said locking means, said electromagnetic drive means being supplied with electric actuating energy.

9. A debarking machine according to claim 3, and further including a hydraulic piston means for actuating said locking means, said hydraulic piston means being fed with hydraulic fluid by a hydraulic pump disposed in the debarking rotor.

10. A debarking machine according to claim 3, comprising additionally a position signal generator for detecting the axial movement of the log to be debarked relative to the debarking rotor and for providing a signal in response to said log reaching an axial position at which the roller-shaped debarking tools can completely engage the log to be debarked, and wherein said locking means responds to said signal by allowing said debarking tools to rotate about said rotational axes.

11. A debarking machine according to claim 1 comprising springs attached to said pivoting arms for biasing said pivot arms toward said log, a drive means mounted on and rotatable with the debarking rotor for varying the spring bias of said pivoting arms.

12. A debarking machine according to claim 11,

wherein is further included a regulator for controlling said drive means to vary said spring bias, said drive means comprising an actual-value-signal generator including a position detector responsive to spring expansion,

13. A debarking machine according to claim l2,

at their outside rotor. 

1. A debarking machine comprising an annular debarking rotor rotating about a log to be debarked and having arms for pivoting about pivot axes located parallel to the rotor axis to press against the log in radial directions relative to the rotor axis, said arms including substantially cylindrical-roller-shaped debarking tools rotating about axes located substantailly parallel to the rotor axis, and said pivoting arms being respectively rotatable about rotational axes extending approximately normal to said pivot axes, said rotational axes being respectively orientated substantially in the longitudinal direction of the pivoting arms.
 2. A debarking machine according to claim 1 in which the rotational axes of said arms constitute substantially tangents to the circumferences of the respective debarking tools in or near to the points of contact with the log to be debarked.
 3. A debarking machine according to claim 1, comprising a locking means for temporarily locking the pivoting arms against rotating movement about said rotational axes.
 4. A debarking machine according to claim 3 wherein said pivot axes and said rotational axes of the pivoting arms intersect each other at respective points and wherein said locking means comprise locking bolts movable coaxially to said pivot axes into bores of shafts being located at said rotational axes.
 5. A debarking machine accordIng to claim 4 wherein said locking bolts are threaded and wherein are further included threaded bushings having toothed rims, a toothed ring for meshing with said threaded bushings and which is coaxial to the debarking rotor, and a servomotor means for rotating said toothed ring.
 6. A debarking machine according to claim 5, wherein said servomotor means comprises an electric motor supplied with electric energy.
 7. A debarking machine according to claim 5, wherein said servomotor means comprises a hydraulic motor supplied with pressurized fluid by a hydraulic pump of the debarking rotor.
 8. A debarking machine according to claim 3, and further including an electromagnetic drive means for actuating said locking means, said electromagnetic drive means being supplied with electric actuating energy.
 9. A debarking machine according to claim 3, and further including a hydraulic piston means for actuating said locking means, said hydraulic piston means being fed with hydraulic fluid by a hydraulic pump disposed in the debarking rotor.
 10. A debarking machine according to claim 3, comprising additionally a position signal generator for detecting the axial movement of the log to be debarked relative to the debarking rotor and for providing a signal in response to said log reaching an axial position at which the roller-shaped debarking tools can completely engage the log to be debarked, and wherein said locking means responds to said signal by allowing said debarking tools to rotate about said rotational axes.
 11. A debarking machine according to claim 1 comprising springs attached to said pivoting arms for biasing said pivot arms toward said log, a drive means mounted on and rotatable with the debarking rotor for varying the spring bias of said pivoting arms.
 12. A debarking machine according to claim 11, wherein is further included a regulator for controlling said drive means to vary said spring bias, said drive means comprising an actual-value-signal generator including a position detector responsive to spring expansion.
 13. A debarking machine according to claim 12, wherein said position detector comprises a potentiometer arranged to be actuated by a movement parallel to the spring expansion movement.
 14. A debarking machine according to claim 1 wherein said debarking tools are formed of outside-rotor electric motors which carry the debarking knives at their outside rotor. 